Opinion polls don't really change the political weather. Like mild breezes, they don't bring down trees, or transform the landscape; but they can make us give the world a second glance. Yesterday's Observer poll showing a sharp narrowing of the gap between Labour and the Conservatives to six points isn't a seismic shift; but it is a useful wakening call. It reminds us that David Cameron PM is not a done deal.

A Guardian poll suggested last week that he was doing better as a trusted and respected individual than was Gordon Brown; and had a 13-point gap, enough for a majority of about 70. But the poll also showed a narrowing between the two main parties. This narrowing might, or might not, continue. It might, or might not, be enough to eventually deprive the Conservatives of a clear win. But its effects are being chewed over with fascination on all sides.

The mismatch between Brown's very bad personal ratings and residual support for Labour was being privately used last week as reason for another move against the prime minister. If these are the figures under Brown, the argument runs, wouldn't an Alan Johnson or David Miliband leadership really put the two parties neck and neck?

Doesn't this explain Miliband's decision not to go for the European job – he realises the game is not yet up in London? It was a big job to turn down and his allies in the government say this was a highly significant move. Indeed – but I'd be wary of expecting anything to happen quickly. At the top, politics is about character and personality – and I just don't see the cabinet plotters with the gumption to shift Brown now, Miliband included.

The prime minister is at least as likely to cite the narrowing gap as evidence that his determination to plug on is being vindicated. He may be hugely unpopular, but he remains a bigger and more determined figure than the rest of them. We must assume that, with the pre-budget report, Copenhagen and then a final budget to oversee, he stays until he determines the election date.

But what if there is then a hung parliament? None of the party leaders would find that easy. For Cameron, after all the buildup, media hype and Tory assumptions of returning power, it would be a terrible blow. Would his personal authority be strong enough to keep a lid on the tensions in his party, particularly over Europe?

Even if he did form a minority government, it would be one committed to swingeing cuts and possibly tax rises – so the opportunities for rebellion and dissent would be enormous. For him to succeed in such circumstances would require strength of character, skill and determination of an order we haven't glimpsed yet. It's the kind of job that broke leaders of the experience of Heath and Callaghan, never mind Major. Actually, given the economic backdrop, it's a bigger task than they ever faced.

Yesterday Nick Clegg, who could emerge as kingmaker, made it clear that he would offer his support first to the party leader who appeared to have "won" the election, though he did not say whether he would base that on number of seats or on raw votes cast. (As an electoral reformer, it should presumably be the latter.)

But the precedent of the general election in February 1974 reminds us that Cameron, even with more MPs, would not have an automatic right to make the first move. Constitutionally he would still be leader of the opposition, as Harold Wilson was, despite Labour winning four more seats than the Conservatives. The prime minister, Ted Heath, tried to stay in Downing Street, making frantic phone calls. It was only after his approaches to the smaller parties were rebuffed that he conceded defeat, and Wilson became prime minister. In stubbornness Brown at least matches Heath: wouldn't he try to "do a Ted"?

One argument doing the rounds in Labour circles is that Brown would be no good at heading any Lib-Lab arrangement. He's a tribalist, and not a natural conciliator. Wouldn't a better partner for Clegg be a new Labour leader committed to PR, and to a reformed political style? Step forward Miliband, with his righthand man Peter Mandelson (no doubt foreign secretary). Tony Blair's brief dream of 1997, of the liberal left reunited, might at last become reality.

Let's not get overexcited. Senior civil servants have been at work for months on the various scenarios if the election produces no clear result. Add in a leadership change to the party still nominally in power, and it becomes utterly chaotic. How could Labour fight the election under one leader, and then do a deal under another leader to stay in power even having lost its Commons majority?

I just don't see that happening. One of the great missed opportunities of the Queen's speech was that the electoral reformers thought they had Brown on the edge of agreeing to include a promise to hold a referendum on PR at the same time as the election. In the end, Brown's caution won out. Had he been bolder, he might have gone a long way to shifting the pre-election political landscape.

So let's assume Clegg goes to speak to Cameron instead. Here he finds an agreeable, civilised chap – who, after all, shares some of his views on civil liberties and localism, and who even tried to invite Clegg round for dinner soon after becoming Tory leader. Here's a man who manages to accommodate both fierce Tory Europhobes and Ken Clarke, and to keep smiling. Here, surely, is a more natural leader for a coalition government?

Yes … except that Cameron is also a million miles from the Lib Dems on Europe, on electoral reform, and on the role of the state. Ideologically, some Lib-Lab arrangement is the likelier outcome of a hung parliament. But it would be a messy and lengthy process, probably drawing Buckingham Palace into the controversy and possibly requiring a second general election.

In public, politicians will reject all this as wildly speculative, while in private they're thinking very hard. But the following things seem safe to say. First, an overall Tory victory is not 100% certain. Second, a minority Tory government would be a very fragile craft. Third, there is a possible Lib-Lab deal to be done if the personalities are right. And fourth – none of this would happen except over months of turmoil.

Up to now, people have looked at next year and thought about either the Liberal breakthrough of 1906, the Tory victory in 1979 or the New Labour breakthrough of 1997. It's beginning to look as if those very turbulent years 1910 and 1974 might be better precedents. I don't know about the market for property or shares – but there are boom times coming for historians, pundits and bloggers.